Splitting from its ancestor, the emperor seaswimmer has become the alpha predator of the Jujubee ocean since its decimation during the solar flare. Doubling in size, it has developed an even thicker, though sleeker, skin in order to keep itself protected as well as streamlined, and has powerful jaw muscles that allow it to bite most of its prey in half. They have evolved a fatty bulge on their lower jaw within which primitive sensory cells have developed which are extremely sensitive to vibrations. Knowing no equal other than those of its own species once fully grown, they have become partially homeothermic.
Now living their entire lives in the water, they no longer need to return to the land. Capable of giving birth at sea, females tend to have four to five pups per litter. The young follow their parents, who still mate for life like their ancestors, and will eventually head off on their own once they reach a quarter of a meter in length. They will then live within the forests of marine bubbleweed for both protection and to exploit the abundant food sources there. Should they survive their childhood, they will eventually fear little once they have matured. Their fat reserves allow them to last weeks without food while attempting to establish a territory, though this is usually done only by fully grown adults who can survive due to their endurance, slow metabolism, and a layer of blubber. This occurs due to they will try to avoid invading the established territories of other emperor seaswimmer. Young ones will remain in the marine bubbleweed forests until they can do this.
While not the fastest creature in the sea, they makes up for this by being well camouflaged. Usually waiting motionlessly, going to surface every eight to twelve minutes in order to breath, they lay in ambush until prey has arrived. In conjunction with their mate, both will rush their prey from beneath, catching them off-guard with a powerful debilitating snap of their jaws. They will also swim along the coasts and the edges of ice sheets, ambushing prey moving in the shallows. They can use their specialized tooth to poke holes through the thinner patches of ice in order to make air holes.